Rocket Validator automatically scans your sites for accessibility issues using the W3C Validator,
hosted on our own servers and integrated into our web crawler.
An attribute could not be parsed from the HTML input, probably due to a typo. Check this guide for a related HTML issue.
Related W3C validator issues
Quote characters used for attributes can use either single quotes (') or double quotes ("), and they must be properly matched, for example:
A common cause for this issue is forgetting to use the equal sign (=), so the HTML parser wrongly believes the quote forms part of the attribute name, for example:
<p class "news">this is wrong</p>